1. Technical Field
The present disclosure relates to a wireless power transmission module for a vehicle, and more particularly, to the wireless power transmission module for a vehicle capable of wireless charging of magnetic induction method and magnetic resonance method.
2. Discussion of the Related Art
Recently, there has been a demand for a wireless charging electronic device, for example a portable terminal such as a mobile phone or a smart phone, a tablet PC, a notebook, a digital broadcasting terminal, a personal digital assistant (PDA), a portable multimedia player (PMP), and the like. Specially, the surrounding environment related to the use of the portable terminal is spreading to a dynamic space such as a vehicle.
Accordingly, a non-contact type charging system using a wireless power transmission method has been proposed so that a battery of a terminal can be easily charged even in a vehicle.
The non-contact type charging system provides electric energy supplied from a vehicle power source to the terminal by the wireless transmission method. The charging system includes a wireless power transmission module embedded in the vehicle, and a wireless power reception module of the terminal to receive the electric energy from the wireless power transmission module.
The non-contact type wireless charging may be classified into a magnetic induction method and a magnetic resonance method, or a power matters alliance (PMA) standard method and a Qi standard method depending on a method of detecting the wireless power reception module accessing to the wireless power transmission module.
The magnetic induction method and the magnetic resonance method described above are the same technologies in that these are using an electromagnetic field and the electromagnetic field is generated by using a coil and electric power is transmitted through the electromagnetic field. However, the magnetic induction method is different from the magnetic resonance method uses electromagnetic resonance between coils whereas the magnetic resonance method uses the electromagnetic resonance between the coils. Further, the operating frequencies of the two methods are different from each other.
For example, the magnetic induction method has an operating frequency band of 100 kHz to 350 kHz, and the magnetic resonance method has an operating frequency band of 6.765 MHz to 6.795 MHz.
Accordingly, there is a problem that the magnetic induction method and the magnetic resonance method are not compatible with each other because their operating frequencies are different from each other.
Meanwhile, in case the magnetic resonance method operating in the high operating frequency band of 6.765 MHz to 6.795 MHz, if the coupling coefficient between the coils is excessively high, the charging efficiency is reduced due to splitting. In case the magnetic induction method operating in the low operating frequency band of 100 kHz to 350 kHz, the higher the coupling coefficient, the higher charging efficiency.
Therefore, in case the magnetic induction method and the magnetic resonance method are applied together, there is a demand for increasing the charging efficiencies through all antennas operating in the magnetic induction method as well as the magnetic resonance method.